What Is Safe Mode?

Bill Gates
Bill Gates speaks during a launch of the Windows Vista operating system. Users can use Safe Mode in Vista as well as earlier versions of Windows. See more Bill Gates pictures.

Operating systems have come a long way, but there are times that they can be frustrating. You're never more than new install away from a computer crash, and a safe mode lockout. But, what is safe mode, how does it work, and what does it mean for your device? It's time to take a closer look.


What is Safe Mode?

Safe mode is a diagnostic mode of a computer operating system or application. It exists as a way to help fix most, if not all problems within an OS. In practice, it creates a restricted environment where only essential system programs and services are allowed to run [source: Beaton].

This makes it easier to diagnose and fix OS related issues that cannot be resolved in the normal operating mode. Safe mode is a critical feature of modern operating systems, and can be found across just about all of them. Windows, Mac, and android devices all lean on their versions of safe mode for this same purpose.


How Safe Mode Works

What a computer or phone is started in safe mode, the OS does not load start-up programs or third party apps and drivers. This means that only the most basic device drivers and files necessary to run the operating system are activated.

For Windows, this includes using a basic graphics display driver, which is why the resolution and functionality in safe mode are lower than in normal mode. Similarly, macOS and Linux distributions load only what is necessary for the system to operate.


What Happens in Safe Mode

There are several things that happen when a device boots in safe mode that differ from a standard boot:

  • Safe Mode does not run the autoexec.bat or config.sys files.
  • Most device drivers are not loaded. A device driver is the software that Windows uses to interact with a piece of hardware, such as a printer or scanner.
  • Instead of the normal graphics device driver, Safe Mode uses standard VGA graphics mode. This mode is supported by all Windows-compatible video cards.
  • Himem.sys, which is normally loaded as part of the config.sys script, is loaded with the /testmem:on switch. This switch tells the computer to test the extended memory before continuing.
  • Safe Mode checks the msdos.sys file for information on where to find the rest of the Windows files. If it finds the files, it proceeds to load Windows in Safe Mode with the command win /d:m. If it does not find the Windows files, it will run command.com to bring up a C: prompt.
  • Windows boots using a batch file called system.cb instead of the standard system.ini file. This file loads the Virtual Device Drivers (VxDs) that Windows uses to communicate with the standard parts of the computer.
  • Windows now loads the regular system.ini file plus win.ini and Registry settings. It skips the [Boot] (except for the shell and device lines) and [386Enh] sections of system.ini and does not load or run any programs listed in win.ini.
  • The Windows desktop loads up in 16 colors and at a resolution of 640 x 480 with the words "Safe Mode" in each corner.

Safe mode starts up automatically if the OS does not boot on the previous attempt. You can also invoke safe mode by pressing F5 or by pressing F8 and selecting it from the boot menu.


­When to Use Safe Mode

Safe mode is particularly useful for troubleshooting and resolving carious computer problems, including:

  • Removing malware: Safe mode won't let malware load properly, making it easier to identify and remove.
  • Fixing software errors: If a recently installed application is causing system instability, booting in safe mode allows the user to uninstall the problematic software.
  • Resolving driver issues: Safe mode can be used to roll back or update drivers that may be causing system crashes or instability.
  • Restoring system stability: If the computer or android device is experiencing random crashes or reboots, safe mode provides a stable environment to perform system restore or other recovery actions.


How to Enable Safe Mode

Enabling safe mode can vary depending on the operating system:

  • Microsoft Windows: In Windows 10 and later, you can access safe mode by restarting the computer while holding the Shift key, then navigating through the troubleshooting options to select safe mode.
  • macOS: Users can boot into safe mode by pressing and holding the shift key immediately after turning on the Mac until the login window appears.
  • Android phones: To restart in safe mode on android devices, press the phone's power button [source: Google]. When the animation starts, press and hold the volume down button until the animation ends and the phone starts in safe mode.


How to Disable Safe Mode

­So what should you do if your computer boots to safe mode? First, try to determine what has changed on your system that could have caused your device to fail to boot properly.

If you have added any kind of hardware, go to the settings panel, remove it, and uninstall the software driver for that device. Then attempt to exit safe mode with a reboot. If the OS boots properly, you can be reasonably certain that there was some type of conflict with the device and try to resolve it.


Use this same method if you have loaded a new game or third party app sometime recently. Go to the settings panel, click on add/remove programs and remove the software.

If the problem is definitely not new hardware or software, then you most likely have a corrupted registry. In this case, you will quite likely have to perform a new installation of the operating system to set things right.


Your Computer's Last Line of Defense

Safe mode is a powerful tool for troubleshooting and fixing issues with computers. By providing a way to load an OS with only the essential files and drivers, it allows users to diagnose and repair problems that would be difficult or impossible to resolve in a normal operating environment.

Whether you're dealing with malware, problematic software, or mysterious system issues, knowing how to access and utilize safe mode can be invaluable in restoring your computer's health and performance.


Safe Mode PC FAQ

What is Safe Mode in a PC?
Safe Mode is a special Windows boot-up that can be used to start the computer when a critical problem that interferes with normal Windows functions and operations has occurred. Safe Mode allows users to troubleshoot and determine the cause behind the malfunction.
When should I use Safe Mode?
Use Safe Mode when you identify a critical problem with your computer or get an error.
What is the difference between Safe Mode and normal mode?
There are many differences between Safe Mode and normal mode. First, Safe Mode doesn't load most of the device drivers or run the autoexec.bat or config.sys files. In this mode, the computer also runs on VGA graphics.